/*
 * EAP peer method: EAP-SIM (RFC 4186)
 * Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "eap_peer/eap_i.h"
#include "eap_config.h"
#include "pcsc_funcs.h"
#include "eap_common/eap_sim_common.h"
#ifdef CONFIG_SIM_SIMULATOR
#include "hlr_auc_gw/milenage.h"
#endif /* CONFIG_SIM_SIMULATOR */


struct eap_sim_data {
        u8 *ver_list;
        size_t ver_list_len;
        int selected_version;
        size_t min_num_chal, num_chal;

        u8 kc[3][EAP_SIM_KC_LEN];
        u8 sres[3][EAP_SIM_SRES_LEN];
        u8 nonce_mt[EAP_SIM_NONCE_MT_LEN], nonce_s[EAP_SIM_NONCE_S_LEN];
        u8 mk[EAP_SIM_MK_LEN];
        u8 k_aut[EAP_SIM_K_AUT_LEN];
        u8 k_encr[EAP_SIM_K_ENCR_LEN];
        u8 msk[EAP_SIM_KEYING_DATA_LEN];
        u8 emsk[EAP_EMSK_LEN];
        u8 rand[3][GSM_RAND_LEN];

        int num_id_req, num_notification;
        u8 *pseudonym;
        size_t pseudonym_len;
        u8 *reauth_id;
        size_t reauth_id_len;
        int reauth;
        unsigned int counter, counter_too_small;
        u8 *last_eap_identity;
        size_t last_eap_identity_len;
        enum {
                CONTINUE, RESULT_SUCCESS, RESULT_FAILURE, SUCCESS, FAILURE
        } state;
        int result_ind, use_result_ind;
};


#ifndef CONFIG_NO_STDOUT_DEBUG
static const char * eap_sim_state_txt(int state)
{
        switch (state) {
        case CONTINUE:
                return "CONTINUE";
        case RESULT_SUCCESS:
                return "RESULT_SUCCESS";
        case RESULT_FAILURE:
                return "RESULT_FAILURE";
        case SUCCESS:
                return "SUCCESS";
        case FAILURE:
                return "FAILURE";
        default:
                return "?";
        }
}
#endif /* CONFIG_NO_STDOUT_DEBUG */


static void eap_sim_state(struct eap_sim_data *data, int state)
{
        wpa_printf(MSG_DEBUG, "EAP-SIM: %s -> %s",
                   eap_sim_state_txt(data->state),
                   eap_sim_state_txt(state));
        data->state = state;
}


static void * eap_sim_init(struct eap_sm *sm)
{
        struct eap_sim_data *data;
        struct eap_peer_config *config = eap_get_config(sm);

        data = os_zalloc(sizeof(*data));
        if (data == NULL)
                return NULL;

        if (os_get_random(data->nonce_mt, EAP_SIM_NONCE_MT_LEN)) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Failed to get random data "
                           "for NONCE_MT");
                os_free(data);
                return NULL;
        }

        data->min_num_chal = 2;
        if (config && config->phase1) {
                char *pos = os_strstr(config->phase1, "sim_min_num_chal=");
                if (pos) {
                        data->min_num_chal = atoi(pos + 17);
                        if (data->min_num_chal < 2 || data->min_num_chal > 3) {
                                wpa_printf(MSG_WARNING, "EAP-SIM: Invalid "
                                           "sim_min_num_chal configuration "
                                           "(%lu, expected 2 or 3)",
                                           (unsigned long) data->min_num_chal);
                                os_free(data);
                                return NULL;
                        }
                        wpa_printf(MSG_DEBUG, "EAP-SIM: Set minimum number of "
                                   "challenges to %lu",
                                   (unsigned long) data->min_num_chal);
                }

                data->result_ind = os_strstr(config->phase1, "result_ind=1") !=
                        NULL;
        }

        eap_sim_state(data, CONTINUE);

        return data;
}


static void eap_sim_deinit(struct eap_sm *sm, void *priv)
{
        struct eap_sim_data *data = priv;
        if (data) {
                os_free(data->ver_list);
                os_free(data->pseudonym);
                os_free(data->reauth_id);
                os_free(data->last_eap_identity);
                os_free(data);
        }
}


static int eap_sim_gsm_auth(struct eap_sm *sm, struct eap_sim_data *data)
{
        struct eap_peer_config *conf;

        wpa_printf(MSG_DEBUG, "EAP-SIM: GSM authentication algorithm");

        conf = eap_get_config(sm);
        if (conf == NULL)
                return -1;
        if (conf->pcsc) {
                if (scard_gsm_auth(sm->scard_ctx, data->rand[0],
                                   data->sres[0], data->kc[0]) ||
                    scard_gsm_auth(sm->scard_ctx, data->rand[1],
                                   data->sres[1], data->kc[1]) ||
                    (data->num_chal > 2 &&
                     scard_gsm_auth(sm->scard_ctx, data->rand[2],
                                    data->sres[2], data->kc[2]))) {
                        wpa_printf(MSG_DEBUG, "EAP-SIM: GSM SIM "
                                   "authentication could not be completed");
                        return -1;
                }
                return 0;
        }

#ifdef CONFIG_SIM_SIMULATOR
        if (conf->password) {
                u8 opc[16], k[16];
                const char *pos;
                size_t i;
                wpa_printf(MSG_DEBUG, "EAP-SIM: Use internal GSM-Milenage "
                           "implementation for authentication");
                if (conf->password_len < 65) {
                        wpa_printf(MSG_DEBUG, "EAP-SIM: invalid GSM-Milenage "
                                   "password");
                        return -1;
                }
                pos = (const char *) conf->password;
                if (hexstr2bin(pos, k, 16))
                        return -1;
                pos += 32;
                if (*pos != ':')
                        return -1;
                pos++;

                if (hexstr2bin(pos, opc, 16))
                        return -1;

                for (i = 0; i < data->num_chal; i++) {
                        if (gsm_milenage(opc, k, data->rand[i],
                                         data->sres[i], data->kc[i])) {
                                wpa_printf(MSG_DEBUG, "EAP-SIM: "
                                           "GSM-Milenage authentication "
                                           "could not be completed");
                                return -1;
                        }
                        wpa_hexdump(MSG_DEBUG, "EAP-SIM: RAND",
                                    data->rand[i], GSM_RAND_LEN);
                        wpa_hexdump_key(MSG_DEBUG, "EAP-SIM: SRES",
                                        data->sres[i], EAP_SIM_SRES_LEN);
                        wpa_hexdump_key(MSG_DEBUG, "EAP-SIM: Kc",
                                        data->kc[i], EAP_SIM_KC_LEN);
                }
                return 0;
        }
#endif /* CONFIG_SIM_SIMULATOR */

#ifdef CONFIG_SIM_HARDCODED
        /* These hardcoded Kc and SRES values are used for testing. RAND to
         * KC/SREC mapping is very bogus as far as real authentication is
         * concerned, but it is quite useful for cases where the AS is rotating
         * the order of pre-configured values. */
        {
                size_t i;
                //Assuming data->num_chal=3
                memcpy(data->kc[0],
                       "\xA0\xA1\xA2\xA3\xA4\xA5\xA6\xA7",
                       EAP_SIM_KC_LEN);
                memcpy(data->sres[0], "\xD1\xD2\xD3\xD4",
                       EAP_SIM_SRES_LEN);
                memcpy(data->kc[1],
                       "\xB0\xB1\xB2\xB3\xB4\xB5\xB6\xB7",
                       EAP_SIM_KC_LEN);
                memcpy(data->sres[1], "\xE1\xE2\xE3\xE4",
                       EAP_SIM_SRES_LEN);
                memcpy(data->kc[2],
                       "\xC0\xC1\xC2\xC3\xC4\xC5\xC6\xC7",
                       EAP_SIM_KC_LEN);
                memcpy(data->sres[2], "\xF1\xF2\xF3\xF4",
                       EAP_SIM_SRES_LEN);

                for (i = 0; i < data->num_chal; i++) {
                   wpa_printf(MSG_DEBUG,"EAP-SIM: Values for %d are:",i);        
                   wpa_hexdump(MSG_DEBUG, "SRES: ",
                               data->sres[i], EAP_SIM_SRES_LEN);
                   wpa_hexdump(MSG_DEBUG, "KC:",
                               data->kc[i], EAP_SIM_KC_LEN);
                   wpa_hexdump(MSG_DEBUG,"Random number:",
                               data->rand[i],16);
               }
                wpa_printf(MSG_DEBUG, "EAP-SIM: Use hardcoded Kc and SRES "
                           "values for testing");
#ifndef CONFIG_CCKM
                for (i = 0; i < data->num_chal; i++) {
                  if (data->rand[i][0] == 0xaa) {
                    os_memcpy(data->kc[i],
                               "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7",
                               EAP_SIM_KC_LEN);
                    os_memcpy(data->sres[i], "\xd1\xd2\xd3\xd4",
                               EAP_SIM_SRES_LEN);
                  } else if (data->rand[i][0] == 0xbb) {
                        os_memcpy(data->kc[i],
                              "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7",
                              EAP_SIM_KC_LEN);
                         os_memcpy(data->sres[i], "\xe1\xe2\xe3\xe4",
                              EAP_SIM_SRES_LEN);
                  } else {
                    os_memcpy(data->kc[i],
                             "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7",
                             EAP_SIM_KC_LEN);
                     os_memcpy(data->sres[i], "\xf1\xf2\xf3\xf4",
                             EAP_SIM_SRES_LEN);
                      }
                      }
#endif
        }

        return 0;

#else /* CONFIG_SIM_HARDCODED */

        wpa_printf(MSG_DEBUG, "EAP-SIM: No GSM authentication algorithm "
                   "enabled");
        return -1;

#endif /* CONFIG_SIM_HARDCODED */
}


static int eap_sim_supported_ver(int version)
{
        return version == EAP_SIM_VERSION;
}


#define CLEAR_PSEUDONYM        0x01
#define CLEAR_REAUTH_ID        0x02
#define CLEAR_EAP_ID        0x04

static void eap_sim_clear_identities(struct eap_sim_data *data, int id)
{
        wpa_printf(MSG_DEBUG, "EAP-SIM: forgetting old%s%s%s",
                   id & CLEAR_PSEUDONYM ? " pseudonym" : "",
                   id & CLEAR_REAUTH_ID ? " reauth_id" : "",
                   id & CLEAR_EAP_ID ? " eap_id" : "");
        if (id & CLEAR_PSEUDONYM) {
                os_free(data->pseudonym);
                data->pseudonym = NULL;
                data->pseudonym_len = 0;
        }
        if (id & CLEAR_REAUTH_ID) {
                os_free(data->reauth_id);
                data->reauth_id = NULL;
                data->reauth_id_len = 0;
        }
        if (id & CLEAR_EAP_ID) {
                os_free(data->last_eap_identity);
                data->last_eap_identity = NULL;
                data->last_eap_identity_len = 0;
        }
}


static int eap_sim_learn_ids(struct eap_sim_data *data,
                             struct eap_sim_attrs *attr)
{
        if (attr->next_pseudonym) {
                os_free(data->pseudonym);
                data->pseudonym = os_malloc(attr->next_pseudonym_len);
                if (data->pseudonym == NULL) {
                        wpa_printf(MSG_INFO, "EAP-SIM: (encr) No memory for "
                                   "next pseudonym");
                        return -1;
                }
                os_memcpy(data->pseudonym, attr->next_pseudonym,
                          attr->next_pseudonym_len);
                data->pseudonym_len = attr->next_pseudonym_len;
                wpa_hexdump_ascii(MSG_DEBUG,
                                  "EAP-SIM: (encr) AT_NEXT_PSEUDONYM",
                                  data->pseudonym,
                                  data->pseudonym_len);
        }

        if (attr->next_reauth_id) {
                os_free(data->reauth_id);
                data->reauth_id = os_malloc(attr->next_reauth_id_len);
                if (data->reauth_id == NULL) {
                        wpa_printf(MSG_INFO, "EAP-SIM: (encr) No memory for "
                                   "next reauth_id");
                        return -1;
                }
                os_memcpy(data->reauth_id, attr->next_reauth_id,
                          attr->next_reauth_id_len);
                data->reauth_id_len = attr->next_reauth_id_len;
                wpa_hexdump_ascii(MSG_DEBUG,
                                  "EAP-SIM: (encr) AT_NEXT_REAUTH_ID",
                                  data->reauth_id,
                                  data->reauth_id_len);
        }

        return 0;
}


static struct wpabuf * eap_sim_client_error(struct eap_sim_data *data, u8 id,
                                            int err)
{
        struct eap_sim_msg *msg;

        eap_sim_state(data, FAILURE);
        data->num_id_req = 0;
        data->num_notification = 0;

        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, EAP_TYPE_SIM,
                               EAP_SIM_SUBTYPE_CLIENT_ERROR);
        eap_sim_msg_add(msg, EAP_SIM_AT_CLIENT_ERROR_CODE, err, NULL, 0);
        return eap_sim_msg_finish(msg, NULL, NULL, 0);
}


static struct wpabuf * eap_sim_response_start(struct eap_sm *sm,
                                              struct eap_sim_data *data, u8 id,
                                              enum eap_sim_id_req id_req)
{
        const u8 *identity = NULL;
        size_t identity_len = 0;
        struct eap_sim_msg *msg;

        data->reauth = 0;
        if (id_req == ANY_ID && data->reauth_id) {
                identity = data->reauth_id;
                identity_len = data->reauth_id_len;
                data->reauth = 1;
        } else if ((id_req == ANY_ID || id_req == FULLAUTH_ID) &&
                   data->pseudonym) {
                identity = data->pseudonym;
                identity_len = data->pseudonym_len;
                eap_sim_clear_identities(data, CLEAR_REAUTH_ID);
        } else if (id_req != NO_ID_REQ) {
                identity = eap_get_config_identity(sm, &identity_len);
                if (identity) {
                        eap_sim_clear_identities(data, CLEAR_PSEUDONYM |
                                                 CLEAR_REAUTH_ID);
                }
        }
        if (id_req != NO_ID_REQ)
                eap_sim_clear_identities(data, CLEAR_EAP_ID);

        wpa_printf(MSG_DEBUG, "Generating EAP-SIM Start (id=%d)", id);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id,
                               EAP_TYPE_SIM, EAP_SIM_SUBTYPE_START);
        if (!data->reauth) {
                wpa_hexdump(MSG_DEBUG, "   AT_NONCE_MT",
                            data->nonce_mt, EAP_SIM_NONCE_MT_LEN);
                eap_sim_msg_add(msg, EAP_SIM_AT_NONCE_MT, 0,
                                data->nonce_mt, EAP_SIM_NONCE_MT_LEN);
                wpa_printf(MSG_DEBUG, "   AT_SELECTED_VERSION %d",
                           data->selected_version);
                eap_sim_msg_add(msg, EAP_SIM_AT_SELECTED_VERSION,
                                data->selected_version, NULL, 0);
        }

        if (identity) {
                wpa_hexdump_ascii(MSG_DEBUG, "   AT_IDENTITY",
                                  identity, identity_len);
                eap_sim_msg_add(msg, EAP_SIM_AT_IDENTITY, identity_len,
                                identity, identity_len);
        }

        return eap_sim_msg_finish(msg, NULL, NULL, 0);
}


static struct wpabuf * eap_sim_response_challenge(struct eap_sim_data *data,
                                                  u8 id)
{
        struct eap_sim_msg *msg;

        wpa_printf(MSG_DEBUG, "Generating EAP-SIM Challenge (id=%d)", id);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, EAP_TYPE_SIM,
                               EAP_SIM_SUBTYPE_CHALLENGE);
        if (data->use_result_ind) {
                wpa_printf(MSG_DEBUG, "   AT_RESULT_IND");
                eap_sim_msg_add(msg, EAP_SIM_AT_RESULT_IND, 0, NULL, 0);
        }
        wpa_printf(MSG_DEBUG, "   AT_MAC");
        eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
        return eap_sim_msg_finish(msg, data->k_aut, (u8 *) data->sres,
                                  data->num_chal * EAP_SIM_SRES_LEN);
}


static struct wpabuf * eap_sim_response_reauth(struct eap_sim_data *data,
                                               u8 id, int counter_too_small)
{
        struct eap_sim_msg *msg;
        unsigned int counter;

        wpa_printf(MSG_DEBUG, "Generating EAP-SIM Reauthentication (id=%d)",
                   id);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id, EAP_TYPE_SIM,
                               EAP_SIM_SUBTYPE_REAUTHENTICATION);
        wpa_printf(MSG_DEBUG, "   AT_IV");
        wpa_printf(MSG_DEBUG, "   AT_ENCR_DATA");
        eap_sim_msg_add_encr_start(msg, EAP_SIM_AT_IV, EAP_SIM_AT_ENCR_DATA);

        if (counter_too_small) {
                wpa_printf(MSG_DEBUG, "   *AT_COUNTER_TOO_SMALL");
                eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER_TOO_SMALL, 0, NULL, 0);
                counter = data->counter_too_small;
        } else
                counter = data->counter;

        wpa_printf(MSG_DEBUG, "   *AT_COUNTER %d", counter);
        eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER, counter, NULL, 0);

        if (eap_sim_msg_add_encr_end(msg, data->k_encr, EAP_SIM_AT_PADDING)) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Failed to encrypt "
                           "AT_ENCR_DATA");
                eap_sim_msg_free(msg);
                return NULL;
        }
        if (data->use_result_ind) {
                wpa_printf(MSG_DEBUG, "   AT_RESULT_IND");
                eap_sim_msg_add(msg, EAP_SIM_AT_RESULT_IND, 0, NULL, 0);
        }
        wpa_printf(MSG_DEBUG, "   AT_MAC");
        eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
        return eap_sim_msg_finish(msg, data->k_aut, data->nonce_s,
                                  EAP_SIM_NONCE_S_LEN);
}


static struct wpabuf * eap_sim_response_notification(struct eap_sim_data *data,
                                                     u8 id, u16 notification)
{
        struct eap_sim_msg *msg;
        u8 *k_aut = (notification & 0x4000) == 0 ? data->k_aut : NULL;

        wpa_printf(MSG_DEBUG, "Generating EAP-SIM Notification (id=%d)", id);
        msg = eap_sim_msg_init(EAP_CODE_RESPONSE, id,
                               EAP_TYPE_SIM, EAP_SIM_SUBTYPE_NOTIFICATION);
        if (k_aut && data->reauth) {
                wpa_printf(MSG_DEBUG, "   AT_IV");
                wpa_printf(MSG_DEBUG, "   AT_ENCR_DATA");
                eap_sim_msg_add_encr_start(msg, EAP_SIM_AT_IV,
                                           EAP_SIM_AT_ENCR_DATA);
                wpa_printf(MSG_DEBUG, "   *AT_COUNTER %d", data->counter);
                eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER, data->counter,
                                NULL, 0);
                if (eap_sim_msg_add_encr_end(msg, data->k_encr,
                                             EAP_SIM_AT_PADDING)) {
                        wpa_printf(MSG_WARNING, "EAP-SIM: Failed to encrypt "
                                   "AT_ENCR_DATA");
                        eap_sim_msg_free(msg);
                        return NULL;
                }
        }
        if (k_aut) {
                wpa_printf(MSG_DEBUG, "   AT_MAC");
                eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
        }
        return eap_sim_msg_finish(msg, k_aut, (u8 *) "", 0);
}


static struct wpabuf * eap_sim_process_start(struct eap_sm *sm,
                                             struct eap_sim_data *data, u8 id,
                                             struct eap_sim_attrs *attr)
{
        int selected_version = -1, id_error;
        size_t i;
        u8 *pos;

        wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Start");
        if (attr->version_list == NULL) {
                wpa_printf(MSG_INFO, "EAP-SIM: No AT_VERSION_LIST in "
                           "SIM/Start");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNSUPPORTED_VERSION);
        }

        os_free(data->ver_list);
        data->ver_list = os_malloc(attr->version_list_len);
        if (data->ver_list == NULL) {
                wpa_printf(MSG_DEBUG, "EAP-SIM: Failed to allocate "
                           "memory for version list");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }
        os_memcpy(data->ver_list, attr->version_list, attr->version_list_len);
        data->ver_list_len = attr->version_list_len;
        pos = data->ver_list;
        for (i = 0; i < data->ver_list_len / 2; i++) {
                int ver = pos[0] * 256 + pos[1];
                pos += 2;
                if (eap_sim_supported_ver(ver)) {
                        selected_version = ver;
                        break;
                }
        }
        if (selected_version < 0) {
                wpa_printf(MSG_INFO, "EAP-SIM: Could not find a supported "
                           "version");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNSUPPORTED_VERSION);
        }
        wpa_printf(MSG_DEBUG, "EAP-SIM: Selected Version %d",
                   selected_version);
        data->selected_version = selected_version;

        id_error = 0;
        switch (attr->id_req) {
        case NO_ID_REQ:
                break;
        case ANY_ID:
                if (data->num_id_req > 0)
                        id_error++;
                data->num_id_req++;
                break;
        case FULLAUTH_ID:
                if (data->num_id_req > 1)
                        id_error++;
                data->num_id_req++;
                break;
        case PERMANENT_ID:
                if (data->num_id_req > 2)
                        id_error++;
                data->num_id_req++;
                break;
        }
        if (id_error) {
                wpa_printf(MSG_INFO, "EAP-SIM: Too many ID requests "
                           "used within one authentication");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        return eap_sim_response_start(sm, data, id, attr->id_req);
}


static struct wpabuf * eap_sim_process_challenge(struct eap_sm *sm,
                                                 struct eap_sim_data *data,
                                                 u8 id,
                                                 const struct wpabuf *reqData,
                                                 struct eap_sim_attrs *attr)
{
        const u8 *identity;
        size_t identity_len;
        struct eap_sim_attrs eattr;

        wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Challenge");
        data->reauth = 0;
        if (!attr->mac || !attr->rand) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Challenge message "
                           "did not include%s%s",
                           !attr->mac ? " AT_MAC" : "",
                           !attr->rand ? " AT_RAND" : "");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        wpa_printf(MSG_DEBUG, "EAP-SIM: %lu challenges",
                   (unsigned long) attr->num_chal);
        if (attr->num_chal < data->min_num_chal) {
                wpa_printf(MSG_INFO, "EAP-SIM: Insufficient number of "
                           "challenges (%lu)", (unsigned long) attr->num_chal);
                return eap_sim_client_error(data, id,
                                            EAP_SIM_INSUFFICIENT_NUM_OF_CHAL);
        }
        if (attr->num_chal > 3) {
                wpa_printf(MSG_INFO, "EAP-SIM: Too many challenges "
                           "(%lu)", (unsigned long) attr->num_chal);
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        /* Verify that RANDs are different */
        if (os_memcmp(attr->rand, attr->rand + GSM_RAND_LEN,
                   GSM_RAND_LEN) == 0 ||
            (attr->num_chal > 2 &&
             (os_memcmp(attr->rand, attr->rand + 2 * GSM_RAND_LEN,
                        GSM_RAND_LEN) == 0 ||
              os_memcmp(attr->rand + GSM_RAND_LEN,
                        attr->rand + 2 * GSM_RAND_LEN,
                        GSM_RAND_LEN) == 0))) {
                wpa_printf(MSG_INFO, "EAP-SIM: Same RAND used multiple times");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_RAND_NOT_FRESH);
        }

        os_memcpy(data->rand, attr->rand, attr->num_chal * GSM_RAND_LEN);
        data->num_chal = attr->num_chal;
                
        if (eap_sim_gsm_auth(sm, data)) {
                wpa_printf(MSG_WARNING, "EAP-SIM: GSM authentication failed");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }
        if (data->last_eap_identity) {
                identity = data->last_eap_identity;
                identity_len = data->last_eap_identity_len;
        } else if (data->pseudonym) {
                identity = data->pseudonym;
                identity_len = data->pseudonym_len;
        } else
                identity = eap_get_config_identity(sm, &identity_len);
        wpa_hexdump_ascii(MSG_DEBUG, "EAP-SIM: Selected identity for MK "
                          "derivation", identity, identity_len);
        eap_sim_derive_mk(identity, identity_len, data->nonce_mt,
                          data->selected_version, data->ver_list,
                          data->ver_list_len, data->num_chal,
                          (const u8 *) data->kc, data->mk);
        eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut, data->msk,
                            data->emsk);
        if (eap_sim_verify_mac(data->k_aut, reqData, attr->mac, data->nonce_mt,
                               EAP_SIM_NONCE_MT_LEN)) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Challenge message "
                           "used invalid AT_MAC");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        /* Old reauthentication and pseudonym identities must not be used
         * anymore. In other words, if no new identities are received, full
         * authentication will be used on next reauthentication. */
        eap_sim_clear_identities(data, CLEAR_PSEUDONYM | CLEAR_REAUTH_ID |
                                 CLEAR_EAP_ID);

        if (attr->encr_data) {
                u8 *decrypted;
                decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
                                               attr->encr_data_len, attr->iv,
                                               &eattr, 0);
                if (decrypted == NULL) {
                        return eap_sim_client_error(
                                data, id, EAP_SIM_UNABLE_TO_PROCESS_PACKET);
                }
                eap_sim_learn_ids(data, &eattr);
                os_free(decrypted);
        }

        if (data->result_ind && attr->result_ind)
                data->use_result_ind = 1;

        if (data->state != FAILURE && data->state != RESULT_FAILURE) {
                eap_sim_state(data, data->use_result_ind ?
                              RESULT_SUCCESS : SUCCESS);
        }

        data->num_id_req = 0;
        data->num_notification = 0;
        /* RFC 4186 specifies that counter is initialized to one after
         * fullauth, but initializing it to zero makes it easier to implement
         * reauth verification. */
        data->counter = 0;
        return eap_sim_response_challenge(data, id);
}


static int eap_sim_process_notification_reauth(struct eap_sim_data *data,
                                               struct eap_sim_attrs *attr)
{
        struct eap_sim_attrs eattr;
        u8 *decrypted;

        if (attr->encr_data == NULL || attr->iv == NULL) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Notification message after "
                           "reauth did not include encrypted data");
                return -1;
        }

        decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
                                       attr->encr_data_len, attr->iv, &eattr,
                                       0);
        if (decrypted == NULL) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Failed to parse encrypted "
                           "data from notification message");
                return -1;
        }

        if (eattr.counter < 0 || (size_t) eattr.counter != data->counter) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Counter in notification "
                           "message does not match with counter in reauth "
                           "message");
                os_free(decrypted);
                return -1;
        }

        os_free(decrypted);
        return 0;
}


static int eap_sim_process_notification_auth(struct eap_sim_data *data,
                                             const struct wpabuf *reqData,
                                             struct eap_sim_attrs *attr)
{
        if (attr->mac == NULL) {
                wpa_printf(MSG_INFO, "EAP-SIM: no AT_MAC in after_auth "
                           "Notification message");
                return -1;
        }

        if (eap_sim_verify_mac(data->k_aut, reqData, attr->mac, (u8 *) "", 0))
        {
                wpa_printf(MSG_WARNING, "EAP-SIM: Notification message "
                           "used invalid AT_MAC");
                return -1;
        }

        if (data->reauth &&
            eap_sim_process_notification_reauth(data, attr)) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Invalid notification "
                           "message after reauth");
                return -1;
        }

        return 0;
}


static struct wpabuf * eap_sim_process_notification(
        struct eap_sm *sm, struct eap_sim_data *data, u8 id,
        const struct wpabuf *reqData, struct eap_sim_attrs *attr)
{
        wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Notification");
        if (data->num_notification > 0) {
                wpa_printf(MSG_INFO, "EAP-SIM: too many notification "
                           "rounds (only one allowed)");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }
        data->num_notification++;
        if (attr->notification == -1) {
                wpa_printf(MSG_INFO, "EAP-SIM: no AT_NOTIFICATION in "
                           "Notification message");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        if ((attr->notification & 0x4000) == 0 &&
            eap_sim_process_notification_auth(data, reqData, attr)) {
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        eap_sim_report_notification(sm->msg_ctx, attr->notification, 0);
        if (attr->notification >= 0 && attr->notification < 32768) {
                eap_sim_state(data, FAILURE);
        } else if (attr->notification == EAP_SIM_SUCCESS &&
                   data->state == RESULT_SUCCESS)
                eap_sim_state(data, SUCCESS);
        return eap_sim_response_notification(data, id, attr->notification);
}


static struct wpabuf * eap_sim_process_reauthentication(
        struct eap_sm *sm, struct eap_sim_data *data, u8 id,
        const struct wpabuf *reqData, struct eap_sim_attrs *attr)
{
        struct eap_sim_attrs eattr;
        u8 *decrypted;

        wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Reauthentication");

        if (data->reauth_id == NULL) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Server is trying "
                           "reauthentication, but no reauth_id available");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        data->reauth = 1;
        if (eap_sim_verify_mac(data->k_aut, reqData, attr->mac, (u8 *) "", 0))
        {
                wpa_printf(MSG_WARNING, "EAP-SIM: Reauthentication "
                           "did not have valid AT_MAC");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        if (attr->encr_data == NULL || attr->iv == NULL) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Reauthentication "
                           "message did not include encrypted data");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
                                       attr->encr_data_len, attr->iv, &eattr,
                                       0);
        if (decrypted == NULL) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Failed to parse encrypted "
                           "data from reauthentication message");
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        if (eattr.nonce_s == NULL || eattr.counter < 0) {
                wpa_printf(MSG_INFO, "EAP-SIM: (encr) No%s%s in reauth packet",
                           !eattr.nonce_s ? " AT_NONCE_S" : "",
                           eattr.counter < 0 ? " AT_COUNTER" : "");
                os_free(decrypted);
                return eap_sim_client_error(data, id,
                                            EAP_SIM_UNABLE_TO_PROCESS_PACKET);
        }

        if (eattr.counter < 0 || (size_t) eattr.counter <= data->counter) {
                wpa_printf(MSG_INFO, "EAP-SIM: (encr) Invalid counter "
                           "(%d <= %d)", eattr.counter, data->counter);
                data->counter_too_small = eattr.counter;
                /* Reply using Re-auth w/ AT_COUNTER_TOO_SMALL. The current
                 * reauth_id must not be used to start a new reauthentication.
                 * However, since it was used in the last EAP-Response-Identity
                 * packet, it has to saved for the following fullauth to be
                 * used in MK derivation. */
                os_free(data->last_eap_identity);
                data->last_eap_identity = data->reauth_id;
                data->last_eap_identity_len = data->reauth_id_len;
                data->reauth_id = NULL;
                data->reauth_id_len = 0;
                os_free(decrypted);
                return eap_sim_response_reauth(data, id, 1);
        }
        data->counter = eattr.counter;

        os_memcpy(data->nonce_s, eattr.nonce_s, EAP_SIM_NONCE_S_LEN);
        wpa_hexdump(MSG_DEBUG, "EAP-SIM: (encr) AT_NONCE_S",
                    data->nonce_s, EAP_SIM_NONCE_S_LEN);

        eap_sim_derive_keys_reauth(data->counter,
                                   data->reauth_id, data->reauth_id_len,
                                   data->nonce_s, data->mk, data->msk,
                                   data->emsk);
        eap_sim_clear_identities(data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);
        eap_sim_learn_ids(data, &eattr);

        if (data->result_ind && attr->result_ind)
                data->use_result_ind = 1;

        if (data->state != FAILURE && data->state != RESULT_FAILURE) {
                eap_sim_state(data, data->use_result_ind ?
                              RESULT_SUCCESS : SUCCESS);
        }

        data->num_id_req = 0;
        data->num_notification = 0;
        if (data->counter > EAP_SIM_MAX_FAST_REAUTHS) {
                wpa_printf(MSG_DEBUG, "EAP-SIM: Maximum number of "
                           "fast reauths performed - force fullauth");
                eap_sim_clear_identities(data, CLEAR_REAUTH_ID | CLEAR_EAP_ID);
        }
        os_free(decrypted);
        return eap_sim_response_reauth(data, id, 0);
}


static struct wpabuf * eap_sim_process(struct eap_sm *sm, void *priv,
                                       struct eap_method_ret *ret,
                                       const struct wpabuf *reqData)
{
        struct eap_sim_data *data = priv;
        const struct eap_hdr *req;
        u8 subtype, id;
        struct wpabuf *res;
        const u8 *pos;
        struct eap_sim_attrs attr;
        size_t len;

        wpa_hexdump_buf(MSG_DEBUG, "EAP-SIM: EAP data", reqData);
        if (eap_get_config_identity(sm, &len) == NULL) {
                wpa_printf(MSG_INFO, "EAP-SIM: Identity not configured");
                eap_sm_request_identity(sm);
                ret->ignore = TRUE;
                return NULL;
        }

        pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SIM, reqData, &len);
        if (pos == NULL || len < 1) {
                ret->ignore = TRUE;
                return NULL;
        }
        req = wpabuf_head(reqData);
        id = req->identifier;
        len = be_to_host16(req->length);

        ret->ignore = FALSE;
        ret->methodState = METHOD_MAY_CONT;
        ret->decision = DECISION_FAIL;
        ret->allowNotifications = TRUE;

        subtype = *pos++;
        wpa_printf(MSG_DEBUG, "EAP-SIM: Subtype=%d", subtype);
        pos += 2; /* Reserved */

        if (eap_sim_parse_attr(pos, wpabuf_head_u8(reqData) + len, &attr, 0,
                               0)) {
                res = eap_sim_client_error(data, id,
                                           EAP_SIM_UNABLE_TO_PROCESS_PACKET);
                goto done;
        }

        switch (subtype) {
        case EAP_SIM_SUBTYPE_START:
                res = eap_sim_process_start(sm, data, id, &attr);
                break;
        case EAP_SIM_SUBTYPE_CHALLENGE:
                res = eap_sim_process_challenge(sm, data, id, reqData, &attr);
                break;
        case EAP_SIM_SUBTYPE_NOTIFICATION:
                res = eap_sim_process_notification(sm, data, id, reqData,
                                                   &attr);
                break;
        case EAP_SIM_SUBTYPE_REAUTHENTICATION:
                res = eap_sim_process_reauthentication(sm, data, id, reqData,
                                                       &attr);
                break;
        case EAP_SIM_SUBTYPE_CLIENT_ERROR:
                wpa_printf(MSG_DEBUG, "EAP-SIM: subtype Client-Error");
                res = eap_sim_client_error(data, id,
                                           EAP_SIM_UNABLE_TO_PROCESS_PACKET);
                break;
        default:
                wpa_printf(MSG_DEBUG, "EAP-SIM: Unknown subtype=%d", subtype);
                res = eap_sim_client_error(data, id,
                                           EAP_SIM_UNABLE_TO_PROCESS_PACKET);
                break;
        }

done:
        if (data->state == FAILURE) {
                ret->decision = DECISION_FAIL;
                ret->methodState = METHOD_DONE;
        } else if (data->state == SUCCESS) {
                ret->decision = data->use_result_ind ?
                        DECISION_UNCOND_SUCC : DECISION_COND_SUCC;
                ret->methodState = data->use_result_ind ?
                        METHOD_DONE : METHOD_MAY_CONT;
        } else if (data->state == RESULT_FAILURE)
                ret->methodState = METHOD_CONT;
        else if (data->state == RESULT_SUCCESS)
                ret->methodState = METHOD_CONT;

        if (ret->methodState == METHOD_DONE) {
                ret->allowNotifications = FALSE;
        }

        return res;
}


static Boolean eap_sim_has_reauth_data(struct eap_sm *sm, void *priv)
{
        struct eap_sim_data *data = priv;
        return data->pseudonym || data->reauth_id;
}


static void eap_sim_deinit_for_reauth(struct eap_sm *sm, void *priv)
{
        struct eap_sim_data *data = priv;
        eap_sim_clear_identities(data, CLEAR_EAP_ID);
        data->use_result_ind = 0;
}


static void * eap_sim_init_for_reauth(struct eap_sm *sm, void *priv)
{
        struct eap_sim_data *data = priv;
        if (os_get_random(data->nonce_mt, EAP_SIM_NONCE_MT_LEN)) {
                wpa_printf(MSG_WARNING, "EAP-SIM: Failed to get random data "
                           "for NONCE_MT");
                os_free(data);
                return NULL;
        }
        data->num_id_req = 0;
        data->num_notification = 0;
        eap_sim_state(data, CONTINUE);
        return priv;
}


static const u8 * eap_sim_get_identity(struct eap_sm *sm, void *priv,
                                       size_t *len)
{
        struct eap_sim_data *data = priv;

        if (data->reauth_id) {
                *len = data->reauth_id_len;
                return data->reauth_id;
        }

        if (data->pseudonym) {
                *len = data->pseudonym_len;
                return data->pseudonym;
        }

        return NULL;
}


static Boolean eap_sim_isKeyAvailable(struct eap_sm *sm, void *priv)
{
        struct eap_sim_data *data = priv;
        return data->state == SUCCESS;
}


static u8 * eap_sim_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
        struct eap_sim_data *data = priv;
        u8 *key;

        if (data->state != SUCCESS)
                return NULL;

        key = os_malloc(EAP_SIM_KEYING_DATA_LEN);
        if (key == NULL)
                return NULL;

        *len = EAP_SIM_KEYING_DATA_LEN;
        os_memcpy(key, data->msk, EAP_SIM_KEYING_DATA_LEN);

        return key;
}


static u8 * eap_sim_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
{
        struct eap_sim_data *data = priv;
        u8 *key;

        if (data->state != SUCCESS)
                return NULL;

        key = os_malloc(EAP_EMSK_LEN);
        if (key == NULL)
                return NULL;

        *len = EAP_EMSK_LEN;
        os_memcpy(key, data->emsk, EAP_EMSK_LEN);

        return key;
}


int eap_peer_sim_register(void)
{
        struct eap_method *eap;
        int ret;

        eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
                                    EAP_VENDOR_IETF, EAP_TYPE_SIM, "SIM");
        if (eap == NULL)
                return -1;

        eap->init = eap_sim_init;
        eap->deinit = eap_sim_deinit;
        eap->process = eap_sim_process;
        eap->isKeyAvailable = eap_sim_isKeyAvailable;
        eap->getKey = eap_sim_getKey;
        eap->has_reauth_data = eap_sim_has_reauth_data;
        eap->deinit_for_reauth = eap_sim_deinit_for_reauth;
        eap->init_for_reauth = eap_sim_init_for_reauth;
        eap->get_identity = eap_sim_get_identity;
        eap->get_emsk = eap_sim_get_emsk;

        ret = eap_peer_method_register(eap);
        if (ret)
                eap_peer_method_free(eap);
        return ret;
}
